Solution: the html select control is disabled and cannot be passed to the background

After the select control is disabled, the foreground value cannot be brought into the background when it is passed to the background. There are two methods available without the readonly attribute: the first method is to unban the read-only attribute of the select control in the method that onSubmit points to when the form is submitted, and then prohibit the select control after the submission. The second method is: <script type = "text/javascript"> var workorderParamParentCode = document. getElementById ("workorderParamParentCode"); var I = workorderParamParentCode. selectedIndex; // it is best to put the function setDefault () {workorderParamParentCode at the bottom of the page. selectedIndex = I ;}</script> as shown in the code above: add this method at the end of the code and add the onChange = "setDefault ()" attribute to the select control.